MECHANISMS OF ADAPTATION AND EXCITATION

描述（改编自申请人的摘要）：该提案将 继续对光转导机制进行长期研究 鲎光感受器。 CaM 激酶与 抑制蛋白的光依赖性磷酸化，但其功能尚不清楚。 CaM 激酶在调节等效光和其他方面的可能作用 转导过程将通过细胞内注射活性物质进行测试 激酶或激酶抑制剂。 第二组实验将尝试 阐明仍未知的转导后期阶段。 这些 实验基于 Ca2+ 升高的假设 由磷脂酶 C (PLC)-IP3 途径产生，触发环化酶；的 由此产生的环核苷酸升高可以激活环 在早期实验中观察到的核苷酸门控通道 补丁。 如果得到证实，这个假设将提供一个完整的途径 从视紫红质到通道以及理解变性的框架 无脊椎动物体内由光产生。 最后一组实验建立在 早期观察发现 CaM 也可能参与了早期步骤 转导。 建议进行生理生化实验 本地化这一步。 初步证据表明它可能位于 PLC。 这些结果如果得到证实，可能会揭示全新的监管机制 对于磷脂酶和 Ca2 ，对于理解可能很重要的见解 这种酶在脊椎动物视锥细胞中的作用，其作用仍然存在 完全不清楚。

DESCRIPTION (Adapted from applicant's abstract): This proposal would continue a long-term investigation of phototransduction mechanisms in Limulus photoreceptors. CaM-kinase has been implicated in the light-dependent phosphorylation of arrestin, but its function is unknown. The possible role of CaM-kinase in regulating equivalent light and other transduction processes will be tested by intracellular injection of active kinase or kinase inhibitors. A second set of experiments will attempt to elucidate the late stages of transduction which remain unknown. These experiments are predicated on the hypothesis that the Ca2+ elevation produced by the phospholipase C (PLC)-IP3 pathway triggers a cyclase; the resulting elevation of cyclic nucleotide could activate the cyclic nucleotide-gated channels observed in earlier experiments on excised patches. If confirmed, this hypothesis would provide a complete pathway from rhodopsin to channel and a framework for understanding the degeneration produced by light in invertebrates. A final set of experiments builds upon the earlier observation that CaM may also be involved in an early step of transduction. Physiological and biochemical experiments are proposed to localize this step. Preliminary evidence suggests that it may be at PLC. These results, if confirmed, may reveal altogether new regulatory mechanisms for phospholipase and Ca2+, insight that may be important in understanding the role of this enzyme in vertebrate cones, where its role remains completely unclear.